[ergyuu]

I can understand the rationale that a natural course of development would ultimately lead to sustainable solutions, yet I can't see how we would necessarily conclude that the "artificial signatures would blend in with those of the natural universe". For example a culture tends to preserve its heritage so I could imagine a sufficiently advanced culture may actually preserve working examples of past technologies. Furthermore, I would assume that provided it is sustainable, the best solution for penetrating the cosmos in search of other lifeforms would be preferred as opposed to those that might mimic the natural universe. If these advanced cultures wanted to encourage contact then they would have overt methods of communication to even num nuts like ourselves. :-))

Makes sense, Copernicus. but then again it would really depend on how sufficiently advanced they are...

[klnbgqr]

It's the best we have and reasonably reliable....similar to measuring cosmological distances with standard candles.

The best we have is a multitude of speculation, based on an understanding that a sample size of one (human civilization) doesn't tell us anything reliable outside of observations of that sample.

Hopefully we are well beyond the egotistical considerations of human (or Western or specific-sociological assumptions of any kind) existence, and don't make any assumptions about others based on our own experience.

We're aiming for rationality here, people. Not only understanding things on the basis of what we think they are, but questioning why we think what we think.

[bloriMal]

To bring things into perspective; we have only had the capability of advertising our existence in the last 100 years or so, yet the universe is 13 odd billion years old. There was something on the news the other day of a planet that could support life some 40 million light years away. If intelligent life was around there then, there is a strong probability that they would now be extinct, based on the time light reaches us and our average species survival rate of only 7 million tears.

It all seems very hit or miss, with mainly miss that two advanced civilisations could not only coexist at the same time, but overcome the immense distances involved to bring them together.

[sensation]

To bring things into perspective; we have only had the capability of advertising our existence in the last 100 years or so, yet the universe is 13 odd billion years old. There was something on the news the other day of a planet that could support life some 40 million light years away. If intelligent life was around there then, there is a strong probability that they would now be extinct, based on the time light reaches us and our average species survival rate of only 7 million tears.

It all seems very hit or miss, with mainly miss that two advanced civilisations could not only coexist at the same time, but overcome the immense distances involved to bring them together.

I agree. Generally, people have a very poor understanding of the implications of "deep time" and vast distances. The liklehood that we co-exist with other technological civilizations, in the immediate interstellar neighborhood or in the universe at large, is vanishingly small, regardless of how many stars there are and even independent of how likely intelligent life is.

[priceyicey]

The best we have is a multitude of speculation, based on an understanding that a sample size of one (human civilization) doesn't tell us anything reliable outside of observations of that sample.
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Slightly more then speculation. We have billions upon billions of planets, and the basic ingrediants for life everywhere we look.
It's not too hard to imagine that the "stuff of life" could have taken a foothold elsewhere.
Most astronomers/astrophysicists/scientists seem to accept that possibility.



>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>
I agree. Generally, people have a very poor understanding of the implications of "deep time" and vast distances. The liklehood that we co-exist with other technological civilizations, in the immediate interstellar neighborhood or in the universe at large, is vanishingly small, regardless of how many stars there are and even independent of how likely intelligent life is.
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The non existence of a universal "now" makes that statement meaningless...Even in our interstellar neighborhood.
Even the man made aspect of "comfort zones" around stars for liquid water to exist, is contained somewhat and is pretty conservative for "life as we know it".



It's also rather obvious that the further along the technically advanced scale we are able to venture, the more likely a civilisation would be to overcome extinction events.

[BrifsGefel]

Alien life, such as bacteria, has been hypothesized to exist in the Solar System and throughout the universe. This hypothesis relies on the vast size and consistent physical laws of the observable universe. According to this argument, made by scientists such as Carl Sagan and Stephen Hawking, it would be improbable for life not to exist somewhere other than Earth.[1][2] This argument is embodied in the Copernican principle, which states that the Earth does not occupy a unique position in the Universe, and the mediocrity principle, which holds that there is nothing special about life on Earth.[3] Life may have emerged independently at many places throughout the Universe. Alternatively life may form less frequently, then spread between habitable planets through panspermia or exogenesis.[4] In any case, complex organic molecules necessary for life may have formed in the protoplanetary disk of dust grains surrounding the Sun before the formation of the Earth based on computer model studies.[5] According to these studies, this same process may also occur around other stars that acquire planets.[5] (Also see Extraterrestrial organic molecules.)





http://en.wikipedia.org/wiki/Extraterrestrial_life
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An hypothesis that could well be shown to be valid before this century is out, and one that echos my own thoughts on the subject, with a leaning towards life arising independently in many places and spread further via "Panspermia".

Again the sheer vastness and great distances between stellar objects and there planets, makes contact difficult.
Again time and distance are the barriers, but also a sufficiently advanced civilisation could overcome these to a certain extent......Maybe a class 2 or 3 civilisation.
We of course have yet to get to class 1, but barring catastrophic calamity I think we will make it before the millenium is half way over.

[escolubtessen]

If a species has a million years on us as far as evolution is concerned, the likelyhood of them being far smarter is obvious. dinosaurs lasted for what? 135 million years? so not necessarily. and that is at least 130 million years on us.

[yqpY4iw6]

sure, but there is no reason to believe that just because a civilization has been around 200,000 years, it will be more advanced than one that has been around for 100,000 years... yes, the roman empire lasted 700 years and while there was a lot of tech advancements the mindset was different to the later europeans who advanced a lot more in a similar time period.

i see the dino argument has been done.

:-)

[diegogo]

THE SUSTAINABILITY SOLUTION TO THE FERMI PARADOX

No present observations suggest a technologically advanced extraterrestrial intelligence (ETI) has spread through the galaxy. However, under commonplace assumptions about galactic civilization formation and expansion, this absence of observation is highly unlikely. This improbability is the heart of the Fermi Paradox. The Fermi Paradox leads some to conclude that humans have the only advanced civilization in this galaxy, either because civilization formation is very rare or because intelligent civilizations inevitably destroy themselves. In this paper, we argue that this conclusion is premature by introducing the "Sustainability Solution" to the Fermi Paradox, which questions the Paradox's assumption of faster (e.g. exponential) civilization growth. Drawing on insights from the sustainability of human civilization on Earth, we propose that faster-growth may not be sustainable on the galactic scale. If this is the case, then there may exist ETI that have not expanded throughout the galaxy or have done so but collapsed. These possibilities have implications for both searches for ETI and for human civilization management.

http://arxiv.org/abs/0906.0568

Xenopsychology

So far we have very little direct knowledge of alien minds --
but we have some fascinating bases for speculation.

There's a story about a psychologist," science fiction writer Murray Leinster once wrote, "who was studying the intelligence of a chimpanzee. He led the chimp into a room full of toys, went out, closed the door and put his eye to the keyhole to see what the chimp was doing. He found himself gazing into a glittering interested brown eye only inches from his own. The chimp was looking through the keyhole to see what the psychologist was doing."

What the psychologist was doing was proceeding on a false assumption; that the subject would behave as expected! Obviously even a creature that looks vaguely human may, or may not act human. How vastly more difficult must it be for us to understand extraterrestrial beings who may look I like nothing we've ever seen before? Certainly we shall be at least as surprised by alien behavior as we are by earthly minds. But evolution is even more important than physical appearance, especially where alien psychology–xenopsychology–is concerned. All living creatures, whether of this world or another, survivors in an endless chain of "winners," organisms whose behavior and sentience allowed them to succeed and increase their numbers.

http://www.rfreitas.com/Astro/Xenopsychology.htm

[Yinekol]

so, the OP proposes one scenario which has possibilities. i suggest there are as many possible scenarios as there are intelligent civilisations in the galaxy.

[sigrekatonov]

yes, the roman empire lasted 700 years and while there was a lot of tech advancements the mindset was different to the later europeans who advanced a lot more in a similar time period.

i see the dino argument has been done.
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Once again for the late "comer inners"....
I said "more likely" and that is the crux....It is far more likely for a civilisation that has been around for 1 million years to be in advance of a civilisation that has been around for 10 years.
Science is full of "reasonable logic" assumptions....DM. DE, the homegenity and Isotropic nature of the Universe.

We all make them everyday.



>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
so, the OP proposes one scenario which has possibilities.
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Yes




>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
i suggest there are as many possible scenarios as there are intelligent civilisations in the galaxy.
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The Opening post didn't suggest otherwise.

[Zaxsdcxs]

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
i suggest there are as many possible scenarios as there are intelligent civilisations in the galaxy.
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And the Opening post just asks about the viability of one more scenario thus....

Do Alien Civilizations Inevitably ‘Go Green’?

[maxfreemann]

Based on chance,,,,
If a species only has ten years of evolution behind it, it is far less likely to have evolved into a technological superior being, then another species with a million years of evolution.

Every species on earth has spent exactly the same amount of time evolving, which is around about several billion years. Ten years of evolution probably only gets you some uncontained biochemical reactions in the soup.

A modern chimpanzee has over a million years extra evolution compared to a Homo erectus, but if you put them side by side it's clear that the earlier one was more technologically advanced.

[Barryrich]

and we are debating the merits. if we just sat back and agreed then this would not be a discussion forum. and it would not serve the purpose for which it was designed.

[MediconStop]

and we are debating the merits. if we just sat back and agreed then this would not be a discussion forum. and it would not serve the purpose for which it was designed.

;-)
I'm not asking anyone to agree. Perhaps you are referring to someone else.
I'm just pointing out the reasonably logical assumption, that in general the longer a species has to evolve, the greater the chances of it reaching our level of intelligence.
Of course we have exceptions....and "lucky breaks" etc...If the dinosaur had not been wiped out the rise of us and mammals may not have eventuated as it did.

[Heacechig]

I'm just pointing out the reasonably logical assumption, that in general the longer a species has to evolve, the greater the chances of it reaching our level of intelligence.

But that's not necessarily true at all. Only one species has reached our level of intelligence, and only one lineage (our own) has spawned anything that's gotten close. There is not enough information to have any confidence about whether such intelligence becomes more common with time or whether it's close to a fixed likelihood from when animal-like organisms first appear. A biosphere could equally likely tick over for a trillion years with no species getting close to what we would call intelligence, or tool users could appear a million years after hitting land.

[cut sifted ephedra sinica]

But that's not necessarily true at all.
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But it would be 100% dinky di not true if it only had 10 years under its belt instead of say a million.

:-)

[Anatolii]

But it would be 100% dinky di not true if it only had 10 years under its belt instead of say a million. that is rather a trivial argument.

[lXvtm0ox]

Coelacanths have had well over 400 million years to 'advance', but I don't see them reaching for the stars just yet.

[BqTyG9eS]

that is rather a trivial argument.

No, not in the least. It states the fact that evolution is slow and needs time.